Small wrapper for Kubernetes that exposes secrets read from files undes /secrets as environemnt variables and then executes desired binary.
It also does Kubernetes style variable expansion in your command arguments, so
variables in form $(MY-VARIABLE) are expanded.
Usage:
greenpeace bash -c echo $(TEST)
If /secrets/test exists, content of that file will be exposed as $TEST and
expanded in commands/arguments if used in form $(TEST).